Bearing for the shafts of measuring instruments.



W. H. PRATT & A. J. R. FIBGO. BEARING FOR THE sHAFTs 0F MEASURINGINSTRUMENTS.

APPLIOATION FILED APB. 22, 1904.

Patented Mar. 3, 1914.

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Inventors. William H.Tratt, .aflxamderega bg 'Z144'.

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Witnesses: 1 Mz 9. 1M.

UNITED STATES PAEENT enuncia.,4

WILLIAM H. PRATT AND ALEXANDER J. R. FIEGO, OF LYNN, MASSACHUSETTS,

ASSIGNORS TO GENERAL ELECTRIC COMIANY, A CORPORATION 0F NEW YORK.

' Specification of Letters Patent.

Application led April 22, 1904. Serial No. 204,338.

To all whom, it may concern Be it known that we, WILLIAM H. PRATT andALEXANDER J. R. Flaco, citizens of the United States, residing at Lynn,countyof Essex, State of Massachusetts, have mvented `certain new anduseful Improve-1 ments in Bearings for the Shafts of MeasuringInstruments, of which the following 1s a specification.

This invention relates to bearings for the shafts of meters or similardelicate instruments in which friction must be eliminated so far as ispossible.

The step bearings commonly employed in meters usually consist of abearing post carrying a spring-supported jewel on which rests the lowerend of the meter-shaft, the latter being provided with a pivot of suit-'able construction. We have found it desirable to have these parts ofthe bearino' combined into a self-contained unit whic may be removedfrom the meter without dislocation. We have therefore provided aremovable pivot for the end of the meter-shaft so arranged that itinterlocks with the bearing post and is therefore removed with thebearing post from the meter.

The novel features which we believe to be characteristic of ourinvention will be detinitely indicated in the claims appended hereto;the details of construction and the mode of operation will be betterunderstood by reference to the following description taken in connectionwith the accompanying drawings which show one embodiment of ourinvention.

In the drawings, Figure 1 is an elevation,

broken away and sectioned in part, of a portion of an integratingwattmeter equipped with our improvements, the meter shown in thedrawings being the well-known Thomson recording wattmeter; Fig. 2 is asectional view of the lower bea'ng; and Fig. 3 is a similar view of aslightly modified form of bearing.

Referring to the drawings, Fig. 1 shows a meter having a rotatable shaft1, an armature 2 carried thereby, field coils 3 for the armature, abrake disk 4 also carried by shaft` 1, and damping magnets 5 coperatingwith disk 4: to retard the rotation of the shaft. The shaft 1 of themeter is prefer- 'ably of tubular form in order to reduce the weight ofthe moving element and extends upward through an opening in the frame 6of the meter, and drives a suitable recordin 4 mechanism which, with thecommutator an upper bearing of the meter, is not shown.

The lower step bearing for the shaft 1 consists of a bearing post 7fittin in a threaded bore in the meter frame 6.

Patented Mar. 3, 1914.

ost 7 is a hollow screw having a plu 8 therein carrying v a jewel 9 andsupportec by a coiled spring 10 The lower end of shaft 1 is providedwith a` pivot 11, carrying a jewel 12 in its lower end and a smallhighly-polished steel ball 13 is 'placed between the jewels 9 and 12, asshown in Fig. 2; or the pivot 11 may be provided with a hardened point14 which rests directly upon the jewel 9, as shown in Fig. 3. Thedistinctive feature of this bearino is that the lower end of the pivot-11 is en arged and the upper end of the bearing post 7 is spun over orcontracted so that the pivot 11 cannot be drawn through the opening inthe upper end of the post 7. By this construction, when the bearing postis removed from the meter the pivot 11 is removed with it, and thebearing postis provided with a removable end-plug 15 in its lower endwhich may be withdrawn to pro vide an opening through which all theparts may be taken out for the purpose of inspection or renewal. Atransverse openin is provided in shaft 1 near its lower end into whichthe upper end of pivot 11 extends to facilitate the removal of the pivotin case it should stick. Secured on the lower end of shaft 1 is asuitable dust guard 16 which extends down over the end of the bearinpost to prevent dust from entering and settlin on the jewel.

We ave shown and described our improvements herein as applied to anintegrating wattmeter but it must be understood that they are applicablegenerally to delicate 1nstruments in which friction must be reduced to aminimum. Also We do not wish to be limited to the precise construction,las many variations can be made therein which we consider within thespirit of our invention and which we aim to cover in the appendedclaims.

What we claim as new and desire to secure by Letters Patent of theUnited States, is:

1. A bearing for the shaft of a measuring instrument comprisinv', apivot for the lower end of the shaft the ower end of the pivot beingenlarged, a bearing post therefor comprising a hollow screw having itsupper end contracted to form an opening about the pivot through whichthe pivot cannot be Withdrawn, and a spring sustained member' in saidscrew supporting the pivot.

2. A bearing for the shaft of a measurin instrument comprising, a pivotfor the eng of the shaft lthe lower portion being enlarged and carryinga jewel, a bearin post therefor comprising a hollow screw with its upperend contracted to form an opening about the pivot through which thepivot .cannot be withdrawn, a spring reeaeee suported member in saidpost carrying a jewe and a ball in operative relation with the twojewels. v

In witness whereof we have hereunto set our hands this twentieth day ofApril, 1904.

WLLIAM H. PRATT. ALEXANDER J. R. FIEGO. Witnesses:

DUGALD MaK. MoKILLoP, JOHN J. WALKER.

